The urinary system generally works to ensure that a person can control micturition. As the bladder fills, muscles stretch and nerves signal the brain that the bladder is full, leading to the urge to urinate. In continent persons, a voluntary decision is then made whether or not to urinate. When it is desirable to not urinate, the spinal cord transmits the message from the brain telling the external sphincter to contract. As the external sphincter contracts, it signals the bladder to relax and the bladder neck to stay closed, and the urge to urinate subsides.
Additionally, the contraction of the sphincter increases the intraurethral pressure, such that it is greater than the intravesical pressure, thereby preventing urine passage through the urethra. This difference between the intravesical pressure and the intra-urethral pressure is termed the urethral closure pressure. When a person desires to void, the brain signals the external sphincter to relax, decreasing pressure in the urethra until urethral pressure is less than the intravesical (bladder) pressure and flow ensues.
Incontinence, or the inability to retain urine, can be broadly divided into five types. Stress incontinence results from an increase in intra-abdominal pressure, which is translated to the bladder, and for which the rhabdosphincter and pelvic floor muscles cannot compensate. Urge incontinence is a sudden need to urinate that is so urgent it cannot be controlled. This may be associated with spasm of the bladder muscle. Mixed incontinence patients experience both stress and urge incontinence. Overflow incontinence occurs when the bladder fails to empty completely due to obstruction. Small amounts of urine are lost because the bladder neck cannot remain closed against the full bladder. The last type of incontinence, functional incontinence, results when mobility limitations prevent the patient from getting to the bathroom; this is often compounded by spinal and/or nerve injury.
There are currently many prosthetic devices available to compensate for incontinence. Many of the devices, however, cause urinary tract infections. Some tend to slip or migrate during use and end up in the bladder, where they may cause a great deal of harm and require invasive surgical procedures for removal. Other devices are permanent devices, which require surgery for implementation and have long-term biocompatibility problems.
For instance, U.S. Pat. No. 5,131,906 to Chen describes a device including a centrally disposed rod or tube member, a truncated spherical shell extending from one end of the member, and a plurality of elastic bands uniformly spaced around the shell periphery. Moreover, U.S. Pat. No. 5,090,424 to Simon et al. describes a flexible urethral plug including a soft inflatable plastic catheter and a transportable fluid which is moved from an external bellows to inflate the catheter within the urethra to block urine flow. Another example of such a device is disclosed in U.S. Pat. No. 5,306,226 to Salama. Salama relates to a urine tube extending through a balloon that is inflated in the neck of the bladder to seal the urethra.
However, all of the above devices suffer from common disadvantages, including a susceptibility to urine encrustation and provision for direct entry of bacteria into the bladder. Additionally, the spherical design of the aforementioned devices may not totally prevent urine leakage. Because of the fluid mechanics inherent with the spherical design, backpressure caused by urine in the bladder may compress a spherical device, while simultaneously causing the urethral walls to expand, allowing urine to leak.
Other prior art incontinence control devices include devices permanently installed within the urethra, such as those disclosed in U.S. Pat. No. 5,114,398 to Trick et al.; U.S. Pat. No. 5,004,454 to Beyar et al.; and U.S. Pat. No. 5,140,999 to Ardito. However, these devices also suffer from some significant disadvantages including the requirement for surgical implantation, inclusion of metal parts subject to corrosion by urine, and need for patient manipulation to permit urination, which may introduce bacteria into the urethra.
Furthermore, temporary incontinence plugs have been previously described by U.S. Pat. No. 5,082,006 to Jonasson and by Nielson et al., xe2x80x9cThe Urethral Plug: A New Treatment Modality for Genuine Urinary Stress Incontinence in Women,xe2x80x9d Journal of Urology144: 1199-1202 (1990). The Jonasson device describes an oblong shaft having at least one knob arranged at a distance from the proximal end of the shaft. This device permits undesirable leakage. Additionally, the device also allows bacteria to enter the urethra. The device described by Nielson et al. includes a tubular shaft having at least one 7 mm sphere located along the shaft. This device, however, may slip during use, allowing the device to migrate into the bladder and require surgical removal. Additionally, this device has no sealing mechanism to prevent urine outflow.
In response to the need for a sealing mechanism, a urethral plug, as described in a Master""s thesis entitled xe2x80x9cDesign of an lntra-Urethral Device for Incontinence,xe2x80x9d by Elizabeth M. Burke (Clemson University Department of Bioengineering, December 1996), was developed to better inhibit urine leakage. In particular, a plug can be positioned in a urethra such that the open end of the plug faces bladder lumen, allowing urine to enter the hollow cavity of the plug. The pressure exerted by urine within the hollow cavity against the plug""s sidewalls causes the sidewalls to outwardly flex in a radial direction and form a seal at the urethral wall.
Nevertheless, while these devices have attempted to address the problem of incontinence, none have been totally successful. As such, a need still exists for a temporary intraurethral device to that is easily insertable by the patient in a sterile manner. A need also exists for a temporary intraurethral device that can substantially inhibit urine leakage when desired and be voluntarily expelled.
In accordance with one embodiment of the present invention, an intraurethral device is provided for use in a female urinary tract. In particular, the intraurethral device contains a urethral plug, a first insertion element, and a second insertion element.
The urethral plug has a distal end and a proximal end. The proximal end defines a plug opening and the distal end is adapted to be inserted into a urethra. For example, in one embodiment, the proximal end of the urethral plug includes a flange for inhibiting over-insertion of the urethral plug into said urethra. Moreover, the distal end has a shape that enables the urethral plug to form a seal with the urethra when inserted therein to substantially inhibit urine leakage from the urethra around the urethral plug. For instance, in one embodiment, the distal end has a shape that forms a generally concave surface, such as a cup-shape.
The first insertion element has an inner surface and an outer surface and at least a portion of the first insertion element is configured to be removably inserted through the plug opening. For example, in one embodiment, the first insertion element contains an elongated element that is configured to be removably inserted through the plug opening defined by the proximal end. In some instances, the first insertion element can also contain an inner body portion having a first end and a second end. For example, the first end of the inner body portion can be connected to the elongated element. Moreover, the second end of the inner body portion can be connected to an outer body portion of the first insertion element.
The second insertion element has an inner surface and an outer surface. The second insertion element defines a channel through which the proximal end of the urethral plug can be inserted. For example, in one embodiment, as stated above, the proximal end of the plug can include a flange that can be inserted through the channel of the second insertion element.
The first insertion and second insertion elements can provide a number of benefits to the intraurethral device. For instance, in many instances, the second insertion element can at least partially surround the urethral plug so that the plug does not come into contact with substantial amounts of bacteria, fungi, or other microorganisms prior to being inserted into a urethra. In addition, the first and second insertion elements can also be placed into operative communication to help in the insertion of the urethral plug into a urethra. For instance, in one embodiment, the inner surface of the second insertion element is placed adjacent to the outer surface of the first insertion element such that the second insertion element is in operative communication with the first insertion element.
In some embodiments, the intraurethral device can also contain additional mechanisms for enhancing the ability of the urethral plug to remain clean and/or sterile prior to and/or during insertion. For example, in one embodiment, an enclosure can be provided that surrounds at least a portion of the urethral plug so that the enclosure is capable of substantially maintaining the cleanliness and/or sterility of the urethral plug before being inserted into the urethra. In one embodiment, the enclosure is attached to the second insertion element.
In accordance with another embodiment of the present invention, a method of substantially inhibiting the leakage of urine from a female urinary tract is provided. Specifically, an intraurethral device, such as described above, is first provided. The urethral plug of the intraurethral device is aligned with the urethra and the urethral plug is inserted therein by moving the first insertion element in a direction towards the urethra and thereafter moving the second insertion element in a direction away from the urethra to substantially release the flange from the second insertion element. For example, in one embodiment, the flange of the urethral plug is initially provided in a rolled-up, U-shape within the second insertion element. By moving the second insertion element away from the urethra, the U-shaped flange can be unrolled into a flat position to inhibit over-insertion of the urethral plug.
Once the urethral plug is inserted, the first insertion element is removed from the plug opening. Due to the shape of the distal end of the urethral plug, a seal can be formed between the urethral plug and the urethra to substantially inhibit urine leakage from the urethra around the urethral plug.
Other features and aspects of the present invention are discussed in greater detail below.